1. Field of the Invention
The present invention relates to a method of driving an information display panel of a passive matrix driving type, in which display media are sealed in a space between two substrates, at least one substrate being transparent, and, in which an electrostatic field, which is generated from an electrode at scan side and an electrode at data side arranged respectively to the opposed substrates in an intersected manner, is applied to the display media so as to display information such as an image.
2. Description of Related Art
As an information display device substitutable for liquid crystal display (LCD), information display devices with the use of technology such as an electrophoresis method, an electro-chromic method, a thermal method, dichroic-particles-rotary method are proposed.
As for these information display devices, it is conceivable as inexpensive visual display device of the next generation from a merit having wide field of vision close to normal printed matter, having smaller consumption with LCD, or having a memory function, and spreading out to a display for portable device and an electronic paper is expected. Recently, electrophoresis method is proposed that microencapsulate dispersion liquid made up with dispersion particles and coloration solution and dispose the liquid between faced substrates, and also it is expected.
However, in the electrophoresis method, there is a problem that a response rate is slow by the reason of viscosity resistance because the particles migrate among the electrophoresis solution. Further, there is a problem of lacking imaging repetition stability, because particles with high specific gravity of titanium oxide is scattered within solution of low specific gravity, it is easy to subside, difficult to maintain a stability of dispersion state. Even in the case of microencapsulating, cell size is diminished to a microcapsule level in order to make it hard to appear, however, an essential problem was not overcome at all.
Besides the electrophoresis method using behavior in the solution, recently, a method wherein electro-conductive particles and a charge transport layer are installed in a part of the substrate without using solution is proposed. [The Imaging Society of Japan “Japan Hardcopy '99” (Jul. 21-23, 1999) Transaction Pages 249-252] However, the structure becomes complicated because the charge transport layer and further a charge generation layer are to be arranged. In addition, it is difficult to constantly dissipate charges from the electro-conductive particles, and thus there is a drawback on the lack of stability.
As one method for overcoming the various problems mentioned above, an information display panel is known, in which at least one or more groups of display media having optical reflectance and charge characteristic, which are constituted by at least one of more groups of particles, are sealed between opposed two substrates, at least one substrate being transparent, and, in which the display media, to which an electrostatic field is applied, are made to move so as to display information such as an image.
In the known information display panel mentioned above, as one example of a method of driving for displaying information such as an image, in order to make a display information stable, there is known a method for applying an intermediate voltage V0 between a voltage VH and a voltage VL used for driving (for example, referred to Japanese Patent Laid-Open Publication No. 2003-248299).
FIG. 27 is a schematic view explaining one embodiment of a known method of driving an information display panel mentioned above. In the embodiment shown in FIG. 27, numerals 51-1 to 51-7 are electrodes at scan side and numerals 52-1 to 52-7 are electrodes at data side arranged in an intersected direction with respect to the electrodes 51-1 to 51-7 at scan side, in which, when information is displayed by scanning the electrodes 51-1 to 51-7 at scan side respectively in this order, a predetermined voltage is applied respectively to the electrodes 51-1 to 51-7 at scan side and the electrodes 52-1 to 52-7 at data side, which construct a matrix electrode, so as to display information such as an image. In this case, in the embodiment shown in FIG. 27, the number of the electrodes at scan side and the number of the electrodes at data side are respectively seven for a convenience of explanation, but actually necessary numbers of the electrodes at scan side and the electrodes at data side may be arranged.
In the embodiment shown in FIG. 27, when information is displayed by performing a scanning operation in an aligning direction of the electrodes 51-1 to 51-7 at scan side, at first, an overall black color display is performed by for example applying a voltage of 0V to the electrodes 51-1 to 51-7 at scan side and a voltage of 80V to the electrode 52-1 to 52-7 at data side. Then, as one example, a voltage of 80V is applied to the selected electrode 51-4 at scan side during writing, and a voltage of 0V is applied to the other non-selected electrodes 51-1 to 51-3 and 51-5 to 51-7 at scan side. In addition, a voltage of 0V is applied to the selected electrode 52-4 at data side during writing, and a voltage of 40V is applied to the other non-selected electrodes 52-1 to 52-3 and 52-5 to 52-7. In this manner, information is displayed.
In the known method of driving an information display panel mentioned above, even in the case such that a white color display or a black color display is maintained in a non-selected region, since a voltage difference of 40V (cross-talk voltage) is generated between the electrode at scan side and the electrode at data side, there is a drawback such that a cross-talk, in which a display becomes a gray color, occurs. Therefore, a display quality of the information display panel becomes sometimes deteriorated.
Here, a cross-talk means generally a phenomenon such that a signal on another line is mixed in a telephonic conversation. However, in this case, a cross-talk means a phenomenon such that an image that differs from actual one is displayed due to an influence of a voltage at data side generated in a non-selected pixel of the electrode at scan side by applying selected or non-selected voltage to lines of the electrodes at data side. Especially, in the display performing a passive matrix driving with respect to the information display panel using the display media mentioned above, a shading of the display is generated due to an influence of cross-talk on the non-selected electrode line at scan side in response to an applied voltage of the electrode at data side, and thus becomes an uneven display.